By the time many sitcoms have reached their fifth season, the characters have started to exaggerate into caricature, as the writers begin to run out of genuine stories to tell about them. Plots grow more outlandish and/or trivial; quirks of personality become more over-the-top; and new characters are introduced in the hope that they’ll freshen things up, while others languish from under-use.

Half of this week’s The Big Bang Theory — the half in which Sheldon spent almost the entire episode at odds with a bird perched on his windowsill — teetered mighty close to that unfortunate TV trap, but ultimately managed to jump over it. The other half of the show, however — the half in which Leonard and Penny went out together on a not-a-date date (i.e. there was no sex at the end of the night) — was one of my favorite Leonard-and-Penny episodes in a long time, precisely because the characters remained firmly, recognizably human, and the writers proved there are still plenty of stories left to tell about these two.

Their not-a-date began after Penny casually asked Leonard if he’d like to come with her to see a movie. At first Leonard balked, wondering if they were ready to go out together just the two of them. But then Penny explained the parameters of the evening: “It’s not a date, Leonard. It’s just a man and a woman hanging out, not having sex at the end of the night.” Of course, Leonard noted that it “sounds like most of dates,” but after they discovered Sheldon freaking out about that aforementioned bird (more on this in a bit), Leonard was up for anything that would get him out of the apartment. But not before he had to endure an unhelpful consultation with Sheldon about the correct attire for a not-a-date. (Turns out it’s what Leonard wears every day.)

After they got to the theater, Leonard’s anxiety about the evening melted away once he realized that being liberated from the possibility of sex meant that he did not have to acquiesce to Penny’s every whim. So instead of seeing the latest Jennifer Aniston movie that’s “an hour-and-a-half of beach houses in the rain until the woman turns around and realizes love was here all along,” he got to insist Penny see the documentary about building a dam in South America. Oh, and she had to pay for her own ticket, too. This wasn’t exactly a revolutionary new salvo in the war of the sexes, I grant you. But watching Leonard finally assert himself — and only because sex was off the table — proved both pretty damn funny and a refreshing new dimension for him to explore.

For her part, being on a non-date meant Penny could flirt with a wannabe screenwriter who she found cute thanks to his “dorky t-shirt and hipster glasses.” When Leonard pointed out that he also wore dorky t-shirts and sported hipster-ish glasses, Penny retorted: “Yes, but when you’re tall and have great cheekbones, you’re doing it ironically.” Now that is a top-notch burn, and it triggered a satisfying back-and-forth between her and Leonard over the other’s romantic shortcomings: He owns two Star Trek uniforms; she thought the Cold War was only fought in winter. Half the dirty movies he owns are animated; she can’t spell asthma. (In all fairness, I had to look up how to spell it just now myself.) But it seems like a bit of a missed opportunity that Penny did not come to any matching revelation about what it’s like to be on a no-sex-attached date with Leonard. Sure, she discovered that she liked the new, assertive, cocky attitude her ex was suddenly taking, but that’s still about Leonard, not her.